Laminates comprising a linear polyarylene sulfoxide adhesive interlaver



United s Patent LAMINATES COMPRISING A LINEAR POLYARYL- ENE SULFOXIDEADHESIVE INTERLAYER Harry A. Smith, Midland, Mich assignor to The DowChemical Company, Midland, Mich., a corporation of Delaware N0 Drawing.Original application Mar. 27, 1963, Ser. No. 268,444. Divided and thisapplication Feb. 28, 1966, Ser. No. 565,330

4 Claims. (Cl. 161-192) This application is a division of applicationSerial No. 268,444, filed March 27, 1963.

The present invention relates to a new and useful class of linearpolyarylene sulfoxides and to a. novel method for their preparation.More particularly the present invention concerns novel sulfoxide resinsand the novel process for preparing the new class of sul-foxides.Further, the present invention concerns laminates and films and fibersproduced employing the sulfoxide resins here disclosed.

It has now been found that a linear polyphenylene sulfide having thegeenral formula iG lQ wherein n represents an integer greater than 1,can be oxidized to its corresponding sulfoxide with nitric acid underanhydrous conditions without oxidation of the sulfur moieties tosu'lfone. Substantially any phenylene sulfide can be oxidized in theforegoing manner, but preferably the present invention relates to theoxidation to sulfoxide of the linear polyphenylene sulfides prepared inthe manner of Macallum, U.S. Patents Nos. 2,513,188 and 2,538,941 orcopending US. patent application Serial No. 85,209, entitled Method forPreparing Linear Polyarylene Sulfides, filed January 27, 1961, by Lenzet al. The polyphenylene sulfoxides of the present invention areprepared by reacting a linear polyarylene sulfide with 6080% nitric acidunder the following conditions:

Temperature -20 C. to about 40 C. Preferred l0 C. to +5 C.

Time 3 to 30' hours.

Preferred to 30 hours.

Pressure Subatmospheric, atmospheric,

superatmospheric. Preferred Atmospheric. Reactant ratios 0.5-1.5 molesHNO' to 1 mole S- unit. Preferred 0.54 HINO to 1.0 --S unit.

The materials prepared by the manner of the present invention areadhesives useful in laminating metals, wood, paper, glass, glass clothand like materials. The sulfoxides are also fiber-forming materials aswell as film forming. The linear sulfoxides of the present invention canbe heated under an inert atmosphere, e. g. argon, to above about 350 C.to about 700 C. for /2 to 100 hours to prepare oxidation stalblematerials which are thermally stable above about 600 C. These lattermaterials are useful as high temperature adhesives, moldingcompositions, films, and the like. Further, the sulfoxide polymers canbe chemically crosslinked by halogenating with bromine or chlorine, thelinear polymer and then reacting the halogenated polymer with Na S toeffect the crosslink. These chemically treated materials are useful asadhesives and can be formed into films. The techniques for these twotreatments are clearly taught in copending applica- CC I tions SerialNo. 268,445, filed of even date herewith,

entitled, Novel Thermal Stable Resins and Products Produced Therewith,and Serial No. 268,471, filed of even date herewith, entitled ChemicallyCrosslinked Polyphenylene Sulfides."

The following examples illustrate the present invention but are not tobe construed as limiting.

Example 1 To a slurry of 5.0 grams of linear phenylene sulfide (preparedin accordance with the technique described in copending applicationSerial No. 85,209 and having a melt viscosity at 303 C. 'of 2000 poises,a melting point of 28-2287 C. and a molecular weight of about 7000) in2.00 ml. of acetic anlrydride cooled to 10 C. was added 1.72 ml. (0.0250mole) of aqueous nitric acid in 50 ml. of acetic anhydride withstirring. The resulting mixture was continuously stirred for 24 hourswhile maintaining the temperature at between 0-5" (3., after which itwas poured into ice-water, neutralized with sodium carbonate andfiltered to recover the polymer. The polymer was slurried in methylenechloride, the slurry filtered, and the filter cake, the polymer, dried.As a result of these operations there was obtained 5.10 grams of polymerrepresenting a yield of 89% based on the starting material. The polymerhad a melting point of 280290 C., a melt viscosity at 303 C. of 2400poises and a molecular weight of 8000 (determined by melt viscosity).The polymer should have a molecular weight of at least 2000. Infnaredanalysis showed no sulfone moieties and no sulfide moieties, onlysulfoxide moieties.

To demonstrate the adhesive quality of the resins of Example 1 of thepresent invention, a laminate bond was prepared by bonding two 1" x 4"17-7 p-H stainless steel bars 0.062" thick (cleaned with methyl ethylketone, scrubbed with scouring powder and water, rinsed, then immersedin aqua regia, rinsed in distilled water and dried) so as to give a V2"lap joint, having the resin of Example 1 therebetween. The bars andpolymer were pressed for 3 hours at 315 C. and under about 1000 lbs. rampressure. A lap shear strength of 560 psi. was obtained using an Instrontest machine according to ASTM Test No. 1002-SST.

It is to be understood that while all references hereinbefore have beenmade to the complete oxidation to the sulfoxide that polymeric materialscan be prepared by only partially oxidizing the sulfur moieties to thesulfoxide, thus to obtain a mixed sulfoxide-sulfide polymeric materialwhich has utility of like character to the sulfoxide and sulfidesdisclosed in this and my copendin-g applications.

I claim:

1. A laminate comprising at least two strata and selected from the groupconsisting of glass, wood and metal and having therebetween a resinhaving the following generic elem wherein n represents an integersuflicient to provide a molecular weight of at least 2000.

2. A laminate as set forth in claim 6 wherein the strata are metal.

3. A laminate as set forth in claim- 6 wherein the strata are glass.

4. A laminate as set forth in claim 6 wherein the strata are glasscloth.

(References on following page) References Cited by the Examiner .7 1OTHER REFERENCES v,

UNITED STATES PATENTS Reid, E. E.: Organic Chemistry of Bivalent Sulfur,2,513,188 6/1950 Macallum 260--79.1X Chem- C09 1960" 2,538,941 1/1951Macallum 26 0 -791 X 5 I 1 2,618,959 11/1952 Watkins 161-187 X EARLB-ERGERT, Prlmm Emmmer- 3,044,961 7/ 19612 y et a1 260 609 X H. ANSH'ER,Assistant Examiner. 3,068,123 12/1962 Fe'ldm an 260'79.3 X

1. A LAMINATE COMPRISING AT LEAST TWO STRATA AND SELECTED FROM THE GROUP CONSISTING OF GLASS, WOOD AND METAL AND HAVING THEREBETWEEN A RESIN HAVING THE FOLLOWING GENERIC STRUCTURE 